Many electronic devices are equipped with a user interface comprising operating keys, a display or both. It is known to provide a slideable cover to protect such a user interface against damage, accidental activation and dust. Alternatively, it may be desirable to conceal the keys or some or all of the display for aesthetic reasons.
In hand held or portable electronic devices, such a slideable cover is usually moved by a user pushing and pulling it back and forth. Since this is a manual action, it may become annoying to the user if it must be repeated numerous times a day, for example in the case of a mobile telephone, whenever the telephone rings. To mitigate this problem certain handheld devices are provided with a spring-loaded mechanism to open the slideable cover in response to actuation of a release button. One example of this is the Nokia® 7110 mobile telephone. An advantage of this arrangement is that it can be simple, small and durable. This facilitates movement of a slideable cover to one direction, for example opening of a slideable cover for answering telephone calls, but even then the user needs to move it manually in the opposite direction.
In CD players which are fixed in location, that is not portable, motorised carriages have been used for receiving and transporting CDs into a playing position. These devices use toothed transmission. Dedicated power sensors are also provided to detect if excessive force is required in order to open or close the carriage. If excessive force is required, the motor is stopped.
Clearly, in a non-portable CD player, there is no problem in providing sufficient operating power to an electrical motor to drive a motorised carriage since it can derive its power from a mains supply or can have a large battery supply. However, in the case of portable CD players, these are usually battery powered with a small battery supply. Therefore, if the power provided by the battery supply falls to too low a level, insufficient operating power may be available to move a carriage for transporting a CD. In order to deal with this difficulty, portable CD players are provided with manually operated hinged covers which cover the playing position. When the playing position is uncovered, a CD is put directly in place without requiring any electrical power.
It is an object of the present invention to facilitate moving of one or more slideable elements of a portable device.